Code clean-up and minor bug fix

pkg/analyzer/lib/src/generated/scanner.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.scanner;
 
 import 'dart:collection';
@@ skipping 2039 matching lines @@
    * The previous token in the token stream.
    */
   Token previous;
 
   /**
    * The next token in the token stream.
    */
   Token _next;
 
   /**
+   * Compare the given [tokens] to find the token that appears first in the
+   * source being parsed. That is, return the left-most of all of the tokens.
+   * The list must be non-`null`, but the elements of the list are allowed to be
+   * `null`. Return the token with the smallest offset, or `null` if there are
+   * no tokens or if all of the tokens are `null`.
+   */
+  static Token lexicallyFirst(List<Token> tokens) {
+    Token first = null;
+    int offset = -1;
+    for (Token token in tokens) {
+      if (token != null && (offset < 0 || token.offset < offset)) {
+        first = token;
+        offset = token.offset;
+      }
+    }
+    return first;
+  }
+
+
+  /**
    * Initialize a newly created token to have the given type and offset.
    *
    * @param type the type of the token
    * @param offset the offset from the beginning of the file to the first character in the token
    */
   Token(this.type, int offset) {
     this.offset = offset;
   }
 
   /**
@@ skipping 613 matching lines @@
    * @param precedingComment the first comment in the list of comments that precede this token
    */
   TokenWithComment(TokenType type, int offset, this._precedingComment) : super(type, offset);
 
   @override
   Token copy() => new TokenWithComment(type, offset, _precedingComment);
 
   @override
   Token get precedingComments => _precedingComment;
 }